The length of time that it takes a plane to reach 30,000 feet is 10 minutes to 20 minutes.
30,000 feet is the cruising altitude of the plane although the exact time can also vary depending on the aircraft type, the aircraft's weight, weather condition and also air traffic control.
Most commercial jets will climb at a rate of 1,000 ft to 2,000 ft per minute, but the rate is often reduced for fuel efficiency.
Heavier aircraft will take longer to reach altitude than lighter weight aircraft.
The reason why planes fly above the clouds is to avoid potentially dangerous weather and turbulent weather.
Flying above the clouds helps planes avoid turbulent and dangerous weather like icing conditions and thunderstorms and turbulence which is common in clouds.
And flying at higher altitudes also increases the planes fuel efficiency as a result of thinner air which reduces drag on the plane and leads to lower fuel consumption and improved speed.
Also flying high and above the clouds helps with air traffic control as well and helps avoid collisions and provides for a more comfortable and much smoother plane ride for the passengers.
Clouds, especially the cumulonimbus clouds, can also contain strong updrafts and even downdrafts, which create dangerous turbulence, and icing conditions which pilots have to avoid.
And flying above the clouds allows for a much more stable and much more comfortable flying experience for the passengers because the air is often calmer and less turbulent above the clouds.
At higher altitudes and above the clouds, the planes engines work more efficiently and use less fuel and also increase the airplanes speed and range.
Flying above the clouds and at higher altitudes also helps the commercial airplane avoid an obstacles like mountains and reduces any conflicts with potential other air traffic, including birds, drones and smaller private aircraft that operate at lower altitudes.
Pilots can avoid dangerous conditions when flying above the clouds, which gives the pilot more time to respond to possible emergencies and ensure a much safer flight for all that are on board the airplane.